dt-bindings: usb: document the Renesas UPD720201/UPD720202 USB 3.0 xHCI Host Controller

dt-bindings: usb: document the Renesas UPD720201/UPD720202 USB 3.0 xHCI Host Controller

Document the Renesas UPD720201/UPD720202 USB 3.0 xHCI Host Controller,
which connects over PCIe and requires specific power supplies to
start up.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260324-topic-sm8650-ayaneo-pocket-s2-upd-bindings-v2-1-b86a1543b76b@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>